Beryllium exposure has been associated with the development of nonmalignant respiratory disease since the 1930s. More recently, the question of a causal association between exposure to beryllium and its compounds and the development of cancer has been raised. Several epidemiologic studies of workers suggest an association between beryllium exposure and lung cancer but are limited by methodologic problems including use of duration of employment as a surrogate measure of exposure. The National Institute for Occupational Safety and Health (NIOSH) has initiated a retrospective cohort mortality study of beryllium- exposed workers in order to resolve the methodologic challenges to the previous studies. Approximately 10,000 individuals fulfill the cohort definition at seven processing plants. A nested case- control study of lung cancer will be conducted to evaluate if exposure to beryllium is related to disease development. This epidemiologic study will be substantially strengthened by the proposed research. The results of the estimated 6,000 environmental samples available at NIOSH and the Nuclear Regulatory Commission, formerly the Atomic Energy Commission, will be used to rank jobs by beryllium exposures. NIOSH does not plan to undertake the exposure assessment; however, the data are available to this investigator. The specific aims of this proposal are: 1. To computerize all environmental data for the beryllium processing plants participating in the NIOSH study, 2. To rank exposures by work area and job title across all plants, and 3. To propose a strategy for reconstructing quantitative estimates of the exposures to beryllium. The ranked exposure estimates will be available to NIOSH for an initial analysis of the case control study.